i think the brake and teether strap is a great idea, i will be buying a strap for my old pram. I found with my DD and DS that my pram would roll down any slight incline. This could be a pram ramp in the street, you know the road crossings, or an uneven carpark.
I would rather wear a tether strap then go through what the two families had to here in Adelaide at the Torrens.